.main-nav {
    height: 100%;
    min-height: 100%;
    position: fixed;
    left: 0;
    top: 0;
    width: 200px;
    background-color: #2bc6ff;
}

.main-nav nav>a {
    display: block;
    height: 30px;
    list-style: none;
    text-decoration: none;
    font-size: 16px;
    color: #fff;
    line-height: 30px;
    text-align: center;
}

.main-nav nav>a:hover,
.main-nav nav>a:active {
    text-decoration: none;
}

main {
    margin-left: 210px;
}

footer {
    position: absolute;
    bottom: 10px;
    right: 10px;
}